1. Field of the Invention
The present invention relates to polyisocyanurate polymers modified with halogenated alcohols, to an improved process for the preparation of polyisocyanurate dispersions, and to cellular and non-cellular polyurethane products prepared from said polyisocyanurate dispersions. More particularly, the invention relates to polyisocyanurate polymers, an improved process for the preparation of polyisocyanurate dispersions of said polymers in polyols, and to cellular and non-cellular polyurethane products with improved flame retardancy prepared employing said dispersions.
2. Description of the Prior Art
The prior art generally teaches the preparation of isocyanurate-modified isocyanate products employing a variety of catalysts. Among these are U.S. Pat. No. 3,996,223 which teaches a process for preparing polyisocyanates containing isocyanurate structures by polymerization in the presence of a mixture of Mannich bases and carbamic acid esters. U.S. Pat. No. 3,645,979 teaches the use of an organic phosphine catalyst to prepare isocyanurate structures. U.S. Pat. No. 3,652,424 teaches a process for the preparation of polyisocyanate compositions containing 5 to 19 percent by weight toluene diisocyanate trimer employing substituted guanidines and isobiguanides as catalysts. U.S. Pat. No. 4,125,491 teaches the preparation of a composition of matter which consists of the reaction product of trimerized toluene diisocyanate with about 0.02 to 0.25 equivalent, based on free isocyanate groups, of an active hydrogen compound which may either be a secondary aliphatic monoamine containing 24 to 36 carbon atoms or a mixture of such amine with an aliphatic alcohol containing 12 to 24 carbon atoms and dispersed in a mixture of toluene and heptane. Not more than 25 percent of the free NCO groups are allowed to react with the active hydrogen compounds. This patent further teaches the use of the dispersions as adhesives or surface coating compositions. Neither the dispersion in polyether polyol or polyester polyol nor the polyurethane compositions using the dispersion of the instant invention are taught in this patent. None of the prior art teaches the preparation of polyisocyanurate polymer which is readily dispersed in a polyol and subsequently employed for the preparation of cellular and non-cellular polyurethane products with improved flame retardancy.